Plastics such as polyesters and polycarbonates have been widely employed, and chemical recycling of these compounds has become increasingly important. In response to customer demands and increasing governmental regulations, leading producers of engineered polymers such as acrylonitrile-butadiene-styrene (ABS), polycarbonate (PC), and PC blends are moving heavily into post-consumer plastics recycling.
Recycling processes can be classified into four major categories a) re-extrusion-primary, b) mechanical-secondary, c) chemical-tertiary, and d) energy recovery-quaternary. Each method provides a unique set of advantages that make it particularly beneficial for specific locations, applications, or requirements. Mechanical recycling (i.e., secondary or material recycling) involves physical treatment, while energy recovery involves complete or partial oxidation of the material producing heat, power, and/or gaseous fuels, oils, and chars. Chemical recycling or depolymerization on the other hand produces chemicals for the chemical industry. Depending upon the chemical agent used to break down the polymer, different depolymerization routes can be envisaged: glycolysis, methanolysis, hydrolysis, ammonolysis, etc.
It would be highly advantageous to have a low-cost source of chemically recycled post-consumer polycarbonate with good properties. The disadvantages of using traditional post-consumer recycle streams, such as water bottle regrinds and ground compact discs, are high cost, cumbersome multi-step process schemes, stability of source/quality of scrap waste, additives present in the recycle plastic, and chemical degradation resulting in inferior product properties.